Absorption type near infrared filter

ABSTRACT

An absorption type near-infrared filter comprising a first multilayer film, a second multilayer film, and an absorption film comprising an infrared absorbing dye with a weight percentage between 1% and 3%, wherein in the infrared band, the difference between the wavelength with the transmittance at 80% of the absorption film and the wavelength with the reflectivity at 80% of the first multilayer film ranges between 130 nm and 145 nm; the difference between the wavelength with the transmittance at 50% of the absorption film and the wavelength with the reflectivity at 50% of the first multilayer film ranges between 75 nm and 90 nm; the difference between the wavelength with the transmittance at 20% of the absorption film and the wavelength with the reflectivity at 20% of the first multilayer film ranges between 25 nm and 45 nm.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Chinese PatentApplication Serial Number 201711371902.6, filed on Dec. 19, 2017, thefull disclosure of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to the technical field of filters, andmore particularly to an absorption type near-infrared filter.

Related Art

Generally, human eyes perceive the visible light wavelength rangingbetween about 400 nm and 700 nm. The invisible light includes infraredhaving a wavelength ranging between 700 nm and 1200 nm and ultraviolethaving a wavelength between ranging 100 nm and 400 nm. Infrared does notaffect color for human vision, but it is not the case for photographicdevices such as cameras, video cameras or cell phone cameras. Aphotographic lens is generally provided with a plurality of opticallenses, filters and image sensing components, such as a charge coupleddevice (CCD) or a complementary metal oxide semiconductor (CMOS), in alens mount. The image sensing component has high sensitivity sensing thelight having a wavelength ranging between 400 nm to 1200 nm, capable ofcapturing infrared in the invisible light. In order to avoid theinfluence of the infrared on the image, a filter or a filtering lensmust be installed in front of the image sensing element to block theinfrared from entering the image sensing element to correct the colorshift phenomenon of the image. At present, the filter includes areflection type filter and an absorption type filter. However, thecurrent filter is prone to have problems such as color shift, chromaticaberration, stray light, or ghosting, thereby affecting the presentationof the photographic image.

SUMMARY

The embodiments of the present disclosure provides an absorption typenear-infrared filter to solve the problems such as color shift,chromatic aberration, stray light, or ghosting, to improve the imagequality.

The present disclosure provides an absorption type near-infrared filtercomprising a first multilayer film, a second multilayer film, and anabsorption film between the first multilayer film and the secondmultilayer film. The absorption film comprises an infrared absorbing dyewith a weight percentage between 1% and 3%, wherein in the infraredband, the difference between the wavelength with the transmittance at80% of the absorption film and the wavelength with the reflectivity at80% of the first multilayer film ranges between 130 nm and 145 nm; thedifference between the wavelength with the transmittance at 50% of theabsorption film and the wavelength with the reflectivity at 50% of thefirst multilayer film ranges between 75 nm and 90 nm; the differencebetween the wavelength with the transmittance at 20% of the absorptionfilm and the wavelength with the reflectivity at 20% of the firstmultilayer film ranges between 25 nm and 45 nm.

It should be understood, however, that this summary may not contain allaspects and embodiments of the present disclosure, that this summary isnot meant to be limiting or restrictive in any manner, and that thedisclosure as disclosed herein will be understood by one of ordinaryskill in the art to encompass obvious improvements and modificationsthereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the exemplary embodiments believed to be novel and theelements and/or the steps characteristic of the exemplary embodimentsare set forth with particularity in the appended claims. The Figures arefor illustration purposes only and are not drawn to scale. The exemplaryembodiments, both as to organization and method of operation, may bestbe understood by reference to the detailed description which followstaken in conjunction with the accompanying drawings in which:

FIG. 1 shows the schematic diagram of an absorption type near-infraredfilter of the present disclosure;

FIG. 2 shows the schematic diagram of the absorption film of the presentdisclosure;

FIG. 3 shows the schematic diagram of another embodiment of theabsorption film of the present disclosure;

FIG. 4 shows the schematic diagram of another embodiment of theabsorption film of the present disclosure;

FIG. 5 shows the infrared spectrum of the absorption type near-infraredfilter of the first embodiment and the second embodiment of the presentdisclosure;

FIG. 6 shows the ultraviolet light spectrum of the absorption typenear-infrared filter of the first embodiment and the second embodimentof the present disclosure;

FIG. 7 shows the infrared spectrum of the absorption type near-infraredfilter of the third embodiment and the fourth embodiment of the presentdisclosure; and

FIG. 8 shows the ultraviolet light spectrum of the absorption typenear-infrared filter of the fourth embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the disclosure are shown. This present disclosure may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this present disclosure will be thorough and complete,and will fully convey the scope of the present disclosure to thoseskilled in the art.

Certain terms are used throughout the description and following claimsto refer to particular components. As one skilled in the art willappreciate, manufacturers may refer to a component by different names.This document does not intend to distinguish between components thatdiffer in name but function. In the following description and in theclaims, the terms “include/including” and “comprise/comprising” are usedin an open-ended fashion, and thus should be interpreted as “includingbut not limited to”. “Substaintial/substaintially” means, within anacceptable error range, the person skilled in the art may solve thetechnical problem in a certain error range to achieve the basictechnical effect. The following description is of the best-contemplatedmode of carrying out the disclosure. This description is made for thepurpose of illustration of the general principles of the disclosure andshould not be taken in a limiting sense. The scope of the disclosure isbest determined by reference to the appended claims.

Moreover, the terms “include”, “contain”, and any variation thereof areintended to cover a non-exclusive inclusion. Therefore, a process,method, object, or device that includes a series of elements not onlyincludes these elements, but also includes other elements not specifiedexpressly, or may include inherent elements of the process, method,object, or device. If no more limitations are made, an element limitedby “include a/an . . . ” does not exclude other same elements existingin the process, the method, the article, or the device which includesthe element.

In the following embodiment, the same reference numerals is used torefer to the same or similar elements throughout the disclosure.

FIG. 1 shows the schematic diagram of an absorption type near-infraredfilter of the present disclosure. As shown in the figure, the absorptiontype near-infrared filter 1 comprises a first multilayer film 10, asecond multilayer film 12, and an absorption film 11 between the firstmultilayer film 10 and the second multilayer film 12. The absorptionfilm 11 of the present disclosure may include only an infraredabsorption film, or a composite absorption film with the capability ofabsorbing infrared and ultraviolet. Alternatively, the absorption film11 may include both an infrared absorption film/layer and an ultravioletabsorption film/layer.

The first multilayer film 10 and the second multilayer film 12 arerespectively stacked by a plurality of layers. The material of eachlayer of the plurality of layers of the first multilayer film 10 and thesecond multilayer film 12 comprises at least one selected from the groupconsisting of TiO₂, SiO₂, Y₂O₃, MgF₂, Al₂O₃, Nb₂O₅, AlF₃, Bi₂O₃, Gd₂O₃,LaF₃, PbTe, Sb₂O₃, SiO, SiN, TA2Os, ZnS, ZnSe, ZrO₂, and Na₃AlF₆. One ofthe first multilayer film 10 and the second multilayer film 12 comprisesan infrared cut structure, and the other comprises an anti-reflectivestructure. The difference between the thickness of the first multilayerfilm 10 and the thickness of the second multilayer film 12 is between 0nm and 4000 nm.

FIG. 2 shows the schematic diagram of the absorption film of the presentdisclosure. The absorption film 11 comprises a transparent substrate 111and a single infrared absorbing layer 112. The transparent substrate 111has a first surface 111 a and a second surface 111 b opposite to thefirst surface 111 a. The first multilayer film 10 or the secondmultilayer film 12 is formed on the first surface 111 a of thetransparent substrate 111, and the infrared absorption layer 112 isformed on the second surface 111 b of the transparent substrate 111. Ifthe first multilayer film 10 is formed on the first surface 111 a of thetransparent substrate 111, the second multilayer film 12 is plated onthe infrared absorbing structure 112 and opposed to the first multilayerfilm 10. If the second multilayer film 12 is formed on the first surface111 a of the transparent substrate 111, the first multilayer film 10 isformed on the infrared absorbing structure 112 and opposed to the secondmultilayer film 12.

The infrared absorbing structure 112 includes a transparent resin and aninfrared absorbing dye. The infrared absorbing dye is dissolved anddispersed in the transparent resin. The material of the transparentresin is selected from the group consisting of epoxy resin,polyacrylate, polyolefin, polycarbonate, polycycloolefin, polyurethane,polyether, polyoxyalkylene and polyvinyl butyral. The transparent resinhas a light transmittance of 85% or more. Alternatively, the transparentresin has a light transmittance of 90% or more. The material of thetransparent substrate 111 comprises, for example, glass, acrylic (PMMA)or quartz. The transparent substrate 111 may comprise an infraredabsorbing coloring material to constitute an infrared absorbingsubstrate. In view of the transparent substrate 111 made of glass, theglass is a fluorophosphate-based infrared filter glass or aphosphate-based infrared filter glass. The weight percentage of theinfrared absorbing dye contained in the absorption film 11 is between 1%and 3%. The material of the infrared absorbing dye comprises at leastone selected from the group consisting of an azo compound, a diimoniumcompound, a dithiophenol metal complex, a phthalocyanine compound, asquaraine compound, and a cyanine compound. Alternatively, the materialof the infrared absorbing dye comprises at least one selected from thegroup consisting of a phthalocyanine compound, a squaraine compound, anda cyanine compound. The wavelength of the light absorbed by the infraredabsorbing dye is between 650 nm and 1100 nm, and alternatively may bebetween 650 nm and 750 nm. The infrared absorbing structure 112 isprepared by preparing an infrared absorbing solution first. The infraredabsorbing solution is a mixture of an infrared absorbing dye and asolvent. The solvent is selected from ketones, ethers, esters, alcohols,alcohol-ethers, hydrocarbons or terpines. The infrared absorbingsolution is further added with a leveling agent, an antistatic agent, alight stabilizer, a heat stabilizer, an antioxidant, a dispersing agent,a flame retardant, a moisturizing agent or a plasticizer. The infraredabsorbing solution is dissolved and dispersed in the transparent resinto form an infrared absorbing coating liquid. Then, the infraredabsorbing coating liquid is applied onto the transparent substrate 111.The coating method may be selected by dip coating, cast coating, spraycoating, spin coating, bead coating, bar coating or knife coating. Theinfrared absorbing coating liquid of the present embodiment is appliedto the transparent substrate 111 by a coating method in which thecoating rotation speed is between 300 rpm and 1100 rpm. After theinfrared absorbing coating liquid is applied onto the transparentsubstrate 111 by the coating method, the infrared absorbing coatingliquid applied to the transparent substrate 111 is sequentiallythermally dried and cured to form the infrared absorbing layer 112 onthe transparent substrate 111. Curing can be performed by using eitherthermal curing or photocuring, or both thermal curing and photocuring.The temperature of the thermal curing is between 100 degrees Celsius and180 degrees Celsius, and the photocuring luminous flux is between 8000J/m² and 10000 J/m².

FIG. 3 shows the schematic diagram of another embodiment of theabsorption film of the present disclosure. The absorption film 11includes a transparent substrate 111, an infrared and ultraviolet mixedabsorbing film 113. The infrared and ultraviolet mixed absorbing film isformed on the transparent substrate 111. The infrared and ultravioletmixed absorbing film 113 is formed by adding an infrared absorbing dyeand an ultraviolet absorbing dye to a transparent resin. The weightpercentage of the infrared absorbing dye contained in the absorptionfilm 11 is between 1% and 3%, and the weight percentage of theultraviolet absorbing dye contained in the absorption film 11 is between4% and 10%. The material of the ultraviolet absorbing dye comprises atleast one selected from the group consisting of an azomethine compound,a lanthanoid compound, a benzotriazole compound, and a triazinecompound. The material of the infrared absorbing dye has been describedabove and will not be described herein. The material of the transparentsubstrate 111 comprises, for example, glass, acryl (PMMA) or quartz. Inanother embodiment, the transparent substrate 111 further contains aninfrared absorbing coloring material to form an infrared absorbingsubstrate. In view of the transparent substrate 111 made of a glassmaterial, the glass is a fluorophosphate-based infrared filter glass ora phosphate-based infrared filter glass.

FIG. 4 shows the schematic diagram of another embodiment of theabsorption film of the present disclosure. The absorption film 11includes a transparent substrate 111 and an infrared and ultravioletlayered absorbing film 114. The infrared and ultraviolet layeredabsorbing film 114 is formed on the transparent substrate 111. Theinfrared and ultraviolet layered absorbing film 114 comprises aninfrared absorption layer 1141 and an ultraviolet absorption layer 1142.The infrared absorbing layer 1141 comprises a transparent resin and aninfrared absorbing dye. The absorption film 11 contains an infraredabsorbing dye in a weight percentage between 1% and 3%; the ultravioletabsorbing layer 1142 comprises a transparent resin and an ultravioletabsorbing dye. The absorption film 11 contains the ultraviolet absorbingdye in a weight percentage between 4% and 10%. In the presentembodiment, the infrared absorbing layer 1141 is formed on thetransparent substrate 111, and the ultraviolet absorbing layer 1142 isformed on the infrared absorbing layer 1141. In another embodiment, thepositions of the infrared absorbing layer 1141 and the ultravioletabsorbing layer 1142 may be reversed. That is, the ultraviolet absorbinglayer 1142 is first provided on the transparent substrate 111, and theinfrared absorbing layer 1141 is provided on the ultraviolet absorbinglayer 1142. In another embodiment, the transparent substrate 111 mayalso include an infrared absorbing pigment. The material of thetransparent resin of the infrared absorbing layer 1141, the material ofthe transparent resin of the ultraviolet absorbing layer 1142, thematerial of the infrared absorbing dye of the infrared absorbing layer1141, the material of the ultraviolet absorbing dye of ultravioletabsorbing layer 1142 have been described above and will not be describedherein. The preparation method of the ultraviolet absorbing layer 1142and the preparation method of the infrared absorbing layer 1141 are thesame as those of the infrared absorbing structure of FIG. 1, and willnot be described herein. The preparation method of the ultravioletabsorbing layer 1142 and the preparation method of the infraredabsorbing layer 1141 are the same as those of the infrared absorbingstructure of FIG. 1, and will not be described herein.

In view of the absorption film 11 being a single infrared absorptionfilm (as shown in FIG. 2), or being an infrared and ultraviolet mixedabsorption film (as shown in FIG. 3) or being an infrared andultraviolet layered absorption film (as shown in FIG. 4), according tothe spectrum of the absorption film 11 and the first multilayer film 10of the present disclosure, the absorption film 11 of the presentdisclosure satisfies the following conditions:

(1) in the infrared band, the difference between the wavelength(λ_(T80%)) with the transmittance at 80% of the absorption film 11 andthe wavelength (λ_(R80%)) with the reflectivity at 80% of the firstmultilayer film 10 ranges between 130 nm and 145 nm;

(2) in the infrared band, the difference between the wavelength(λ_(T50%)) with the transmittance at 50% of the absorption film 11 andthe wavelength (λ_(R50%)) with the reflectivity at 50% of the firstmultilayer film 10 ranges between 75 nm and 90 nm;

(3) in the infrared band, the difference between the wavelength(λ_(T20%)) with the transmittance at 20% of the absorption film 11 andthe wavelength (λ_(R20%)) with the reflectivity at 20% of the firstmultilayer film 10 ranges between 25 nm and 45 nm;

(4) in the infrared band, the absolute difference between the wavelength(λ_(T80%)) with the transmittance at 80% of the absorption film 11 andthe wavelength (λ_(T50%)) with the transmittance at 50% of theabsorption film 11 is lower than 50 nm;

(5) in the infrared band, the absolute difference between the wavelength(λ_(T50%)) with the transmittance at 50% of the absorption film 11 andthe wavelength (λ_(T20%)) with the transmittance at 20% of theabsorption film 11 is lower than 42 nm.

In view of the absorption film 11 being a single composite absorptionfilm with infrared and ultraviolet absorption function (as shown in FIG.3), or being a combination of the infrared absorption film and theultraviolet absorption film (as shown in FIG. 4), according to thespectrum of the absorption film 11 and the first multilayer film 10 ofthe present disclosure, the absorption film 11 of the present disclosuresatisfies the following conditions:

(1) in the ultraviolet band, the difference between the wavelength(λ_(T80%)) with the transmittance at 80% of the absorption film 11 andthe wavelength (λ_(R80%)) with the reflectivity at 80% of the firstmultilayer film 10 ranges between 23 nm and 40 nm;

(2) in the ultraviolet band, the difference between the wavelength(λ_(T50%)) with the transmittance at 50% of the absorption film 11 andthe wavelength (λ_(R50%)) with the reflectivity at 50% of the firstmultilayer film 10 ranges between 3 nm and 14 nm;

(3) in the ultraviolet band, the difference between the wavelength(λ_(T20%)) with the transmittance at 20% of the absorption film 11 andthe wavelength (λ_(R20%)) with the reflectivity at 20% of the firstmultilayer film 10 ranges between −15 nm and 2.5 nm;

(4) in the ultraviolet band, the absolute difference between thewavelength (λ_(T80%)) with the transmittance at 80% of the absorptionfilm 11 and the wavelength (λ_(T50%)) with the transmittance at 50% ofthe absorption film 11 is lower than 23 nm;

(5) in the ultraviolet band, the absolute difference between thewavelength (λ_(T50%)) with the transmittance at 50% of the absorptionfilm 11 and the wavelength (λ_(T20%)) with the transmittance at 20% ofthe absorption film 11 is lower than 16 nm;

(6) the difference between the wavelength (λ_(T80%)) with thetransmittance at 80% of the absorption film 11 in the infrared band andthe wavelength (λ_(T80%)) with the transmittance at 80% of theabsorption film 11 in the ultraviolet band ranges between 126 nm and 164nm;

(7) the difference between the wavelength (λ_(T50%)) with thetransmittance at 50% of the absorption film 11 in the infrared band andthe wavelength (λ_(T50%)) with the transmittance at 50% of theabsorption film 11 in the ultraviolet band ranges between 195 nm and 239nm;

(8) the difference between the wavelength (λ_(T20%)) with thetransmittance at 20% of the absorption film 11 in the infrared band andthe wavelength (λ_(T20%)) with the transmittance at 20% of theabsorption film 11 in the ultraviolet band ranges between 244 nm and 309nm.

First Embodiment

The structure of the absorption type near-infrared filter of theembodiment comprises a single infrared absorption film, and the infraredabsorption film comprises an infrared absorption dye. The thickness ofthe first multilayer film of the embodiment is between 4000 nm and 4500nm. The thickness of the two-layered film structure is between 600 nmand 700 nm. The first multilayer film and the second multilayer film inthis embodiment are asymmetrically coated, as shown in FIG. 2.

Table 1 provides the actual data for ten sets of absorption films. Theabsorption film of the embodiment is a single infrared absorption filmA1. The weight percentage of the infrared absorbing dye of the infraredabsorbing structure A1 of each set is different. The rotating speed forforming the infrared absorbing structure A1 between 400 rpm and 650 rpm.Refer to FIG. 5 illustrating the first transmittance spectrum curve 21,the second transmittance spectrum curve 22, the third transmittancespectrum curve 23, the fourth transmittance spectrum curve 24, and thefirst reflectivity spectrum curve 25. The first transmittance spectrumcurve 21, the second transmittance spectrum curve 22, the thirdtransmittance spectrum curve 23, and the fourth transmittance spectrumcurve 24 respectively illustrate the transmittance spectrum curve of theinfrared absorption film A1 in the infrared band for No. 1, No. 2, No. 5and No. 10 in the following table. The first reflectivity spectrum curve25 is a reflectivity spectrum curve of the first multilayer film R1 inthe infrared band.

According to the spectrum curve of the infrared absorbing structure A1and the first multilayer film R1 (FIG. 5), in the infrared band, thedifference (A1 (λ_(T80%))−R1 (λ_(R80%))) between the wavelength(λ_(T80%)) with the transmittance at 80% of the infrared absorption filmA1 and the wavelength (λ_(R80%)) with the reflectivity at 80% of thefirst multilayer film R1, the difference (A1 (λ_(T50%))−R1 (λ_(R50%)))between the wavelength (λ_(T50%)) with the transmittance at 50% of theinfrared absorption film A1 and the wavelength (λ_(R50%)) with thereflectivity at 50% of the first multilayer film R1, the difference (A1(λ_(T20%))−R1 (λ_(R20%))) between the wavelength (λ_(T20%)) with thetransmittance at 20% of the infrared absorption film A1 and thewavelength (λ_(R20%)) with the reflectivity at 20% of the firstmultilayer film R1, the difference (Δλ_((0°−30°)T50%)) between theincident angle 0 degrees to 30 degrees with the transmittance at 50% ofthe infrared absorption film A1, and the difference (Δλ_((0°−30°)T20%))between the incident angle 0 degrees to 30 degrees with thetransmittance at 20% of the infrared absorption film A1 are calculated.

TABLE 1 No. 1 2 3 4 5 Infrared absorbing dye 0.68 0.94 1.24 1.47 1.53(%) Transparent resin (%) 100 100 100 100 100 A1 (λ_(T80%))-R1(λ_(R80%))129.3 133.2 135.8 137.0 137.7 (nm) A1 (λ_(T50%))-R1(λ_(R50%)) 61.1 70.977.1 79.0 79.8 (nm) A1 (λ_(T20%))-R1(λ_(R20%)) 5.8 21.2 28.2 30.6 32.1(nm) Δλ_((0°-30°)T50%) 3.9 3.0 1.9 1.8 1.7 Δλ_((0°-30°)T20%) 20.8 10.06.0 5.0 4.5 No. 6 7 8 9 10 Infrared absorbing dye 1.58 1.75 1.83 2.022.73 (%) Transparent resin (%) 100 100 100 100 100 A1(λ_(T80%))-R1(λ_(R80%)) 139.0 139.5 140.3 141.3 142.3 (nm) A1(λ_(T50%))-R1(λ_(R50%)) 82.0 83.0 83.6 84.3 86.7 (nm) A1(λ_(T20%))-R1(λ_(R20%)) 34.2 35.5 37.5 39.4 41.8 (nm) Δλ_((0°-30°)T50%)1.6 1.6 1.6 1.6 1.7 Δλ_((0°-30°)T20%) 4.0 3.7 3.4 3.0 2.7

It may be summarized from No. 3 to No. 10 in the above Table 1. Theweight percentage of the infrared absorbing dye contained in theinfrared absorbing structure A1 is controlled to be between 1% and 3%,and the rotation speed for forming the infrared absorbing structure A1is controlled between 400 rpm and 650 rpm. The spectrum of each of theinfrared absorbing structure A1 and the first multilayer film R1satisfies the following conditions: the difference of between thewavelength with the transmittance at 80% of the infrared absorption filmA1 and the wavelength with the reflectivity at 80% of the firstmultilayer film R1 falls in the range between 135 nm and 145 nm, thedifference of between the wavelength with the transmittance at 50% ofthe infrared absorption film A1 and the wavelength with the reflectivityat 50% of the first multilayer film R1 falls in the range between 75 nmand 90 nm, and the difference of between the wavelength with thetransmittance at 20% of the infrared absorption film A1 and thewavelength with the reflectivity at 20% of the first multilayer film R1falls in the range between 25 nm and 45 nm.

When the spectrum of the infrared absorbing structure A1 satisfies theabove conditions, the difference between the incident angle 0 degrees to30 degrees with the transmittance at 50% of the infrared absorption filmA1 is less than 2 nm, and the difference between the incident angle 0degrees to 30 degrees with the transmittance at 20% of the infraredabsorption film A1 is less than 6 nm. This indicates the offset of thespectrum curves between the incident angles from 0 degrees to 30 degreesfor the infrared absorption film A1 is small. The problems of colorshift, chromatic aberration, stray light and ghosting caused by thecoating of the near-infrared filter is effectively solved. Thetransparent substrate of the infrared absorbing structure A1 of thepresent embodiment may also contain an infrared absorbing coloringmaterial to achieve the above effects.

Second Embodiment

Different from the absorption type near-infrared filter in the firstembodiment, the absorption type near-infrared filter of the presentembodiment adopts an infrared and ultraviolet mixed absorbing film A2.The infrared and ultraviolet absorbing layer absorbing structure A2 hasan infrared absorbing dye and an ultraviolet absorbing dye, as shown inFIG. 3.

Table 2 below provides actual data for ten sets of absorption films. Theabsorption film is an infrared and ultraviolet mixed layer absorptionfilm A2. The weight percentage of the infrared absorbing dye and theultraviolet absorbing dye of each infrared and ultraviolet mixed layerabsorption film A2 is different. The rotating speed for coating formingthe infrared absorbing structure A2 between 400 rpm and 650 rpm. Referto FIG. 5 and FIG. 6. The spectrum curves in the infrared band of theinfrared and ultraviolet mixed layer absorption film A2 and the firstmultilayer film R1 of the second embodiment are similar to the infraredabsorption film A1 and the first multilayer film R1 of the firstembodiment. Therefore, the spectrum curve of the infrared andultraviolet mixed layer absorption film A2 in the infrared band of thisembodiment may refer to FIG. 5. FIG. 6 includes the fifth transmittancespectrum curve 31, the sixth transmittance spectrum curve 32, theseventh transmittance spectrum curve 33, the eighth transmittancespectrum curve 34, and the second reflectivity spectrum curve 35. Thefifth transmittance spectrum curve 31, the sixth transmittance spectrumcurve 32, the seventh transmittance spectrum curve 33, the eighthtransmittance spectrum curve 34 respectively illustrate thetransmittance spectrum curve of the infrared and ultraviolet mixed layerabsorption film A2 in the ultraviolet band for No. 1, No. 2, No. 5 andNo. 10 in the following table. The second reflectivity spectrum curve 35is a reflectivity spectrum curve of the first multilayer film R1 in theultraviolet band.

According to the spectrum curve of the infrared and ultraviolet mixedlayer absorption film A2 and the first multilayer film R1 (FIG. 5), inthe infrared band, the difference (A2 (λ_(T80%))−R1 (λ_(R80%))) betweenthe wavelength (λ_(T80%)) with the transmittance at 80% of the infraredand ultraviolet mixed layer absorption film A2 and the wavelength(λ_(R80%)) with the reflectivity at 80% of the first multilayer film R1,the difference (A2(λ_(T50%))−R1(λ_(R50%))) between the wavelength(λ_(T50%)) with the transmittance at 50% of the infrared and ultravioletmixed layer absorption film A2 and the wavelength (λ_(R50%)) with thereflectivity at 50% of the first multilayer film R1, the difference (A2(λ_(T20%))−R1 (λ_(R20%))) between the wavelength (λ_(T20%)) with thetransmittance at 20% of the infrared and ultraviolet mixed layerabsorption film A2 and the wavelength (λ_(R20%)) with the reflectivityat 20% of the first multilayer film R1, the difference(Δλ_((0°−30°)T50%)) between the incident angle 0 degrees to 30 degreeswith the transmittance at 50% of the infrared and ultraviolet mixedlayer absorption film A2, and the difference (Δλ_((0°−30°)T20%)) betweenthe incident angle 0 degrees to 30 degrees with the transmittance at 20%of the infrared and ultraviolet mixed layer absorption film A2 arecalculated.

According to the spectrum curve of the infrared and ultraviolet mixedlayer absorption film A2 and the first multilayer film R1 (FIG. 6), inthe ultraviolet band, the difference (A2 (λ_(T80%))−R1 (λ_(R80%)))between the wavelength (λ_(T80%)) with the transmittance at 80% of theinfrared and ultraviolet mixed layer absorption film A2 and thewavelength (λ_(R80%)) with the reflectivity at 80% of the firstmultilayer film R1, the difference (A2 (λ_(T50%))−R1 (λ_(R50%))) betweenthe wavelength (λ_(T50%)) with the transmittance at 50% of the infraredand ultraviolet mixed layer absorption film A2 and the wavelength(λ_(R50%)) with the reflectivity at 50% of the first multilayer film R1,the difference (A2 (λ_(T20%))−R1 (λ_(R20%))) between the wavelength(λ_(T20%)) with the transmittance at 20% of the infrared and ultravioletmixed layer absorption film A2 and the wavelength (λ_(R20%)) with thereflectivity at 20% of the first multilayer film R1, the difference(Δλ_((0°−30°)T50%)) between the incident angle 0 degrees to 30 degreeswith the transmittance at 50% of the infrared and ultraviolet mixedlayer absorption film A2, and the difference (Δλ_((0°−30°)T20%)) betweenthe incident angle 0 degrees to 30 degrees with the transmittance at 20%of the infrared and ultraviolet mixed layer absorption film A2 arecalculated.

TABLE 2 No. 1 2 3 4 5 Infrared absorbing dye 0.68 0.94 1.24 1.47 1.53(%) Ultraviolet absorbing dye 2.7 3.5 4.2 5.28 7.68 (%) Transparentresin (%) 100 100 100 100 100 No. 6 7 8 9 10 Infrared absorbing dye 1.581.75 1.83 2.02 2.73 (%) Ultraviolet absorbing dye 7.94 8.58 8.94 9.239.54 (%) Transparent resin (%) 100 100 100 100 100 IN THE INFRARED BANDNo. 1 2 3 4 5 A2 (λ_(T80%))-R1 (λ_(R80%)) 129.3 133.2 135.8 137.0 137.7(nm) A2 (λ_(T50%))-R1 (λ_(R50%)) 61.1 70.9 77.1 79.0 79.8 (nm) A2(λ_(T20%))-R1 (λ_(R20%)) 5.8 21.2 28.2 30.6 32.1 (nm) Δλ_((0°-30°)T50%)3.9 3.0 1.9 1.8 1.7 Δλ_((0°-30°)T20%) 20.8 10.0 6.0 5.0 4.5 No. 6 7 8 910 A2 (λ_(T80%))-R1 (λ_(R80%)) 139.0 139.5 140.3 141.3 142.3 (nm) A2(λ_(T50%))-R1 (λ_(R50%)) 82.0 83.0 83.6 84.3 86.7 (nm) A2 (λ_(T20%))-R1(λ_(R20%)) 34.2 35.5 37.5 39.4 41.8 (nm) Δλ_((0°-30°)T50%) 1.6 1.6 1.61.6 1.7 Δλ_((0°-30°)T20%) 4.0 3.7 3.4 3.0 2.7 IN THE ULTRAVOILET BANDNo. 1 2 3 4 5 A2 (λ_(T80%))-R1 (λ_(R80%)) (nm) 16.5 20.3 24.4 26.5 28.3A2 (λ_(T50%))-R1 (λ_(R50%)) (nm) −3.8 −0.8 3.2 5.2 6.8 A2 (λ_(T20%))-R1(λ_(R20%)) (nm) −27.8 −20.4 −12.6 −9.5 −7.3 Δλ_((0°-30°)T50%) 7.1 5.01.9 0.5 −0.4 Δλ_((0°-30°)T20%) 10.9 10.4 8.9 7.5 6.0 No. 6 7 8 9 10 A2(λ_(T80%))-R1 (λ_(R80%)) (nm) 30.1 31.5 33.5 35.6 38.2 A2 (λ_(T50%))-R1(λ_(R50%)) (nm) 8.2 9.2 10.2 11.1 12.0 A2 (λ_(T20%))-R1 (λ_(R20%)) (nm)−5.3 −3.8 −2.5 −1.3 −0.3 Δλ_((0°-30°)T50%) −0.9 −1.1 −1 −1 −1Δλ_((0°-30°)T20%) 4.6 3.4 2.5 1.8 1.2

It may be summarized from No. 3 to No. 10 in the above Table 2. Theweight percentage of the infrared absorbing dye contained in theinfrared and ultraviolet mixed absorbing film A2 is controlled to bebetween 1% and 3%, the weight percentage of the ultraviolet absorbingdye contained in the infrared and ultraviolet mixed absorbing film A2 iscontrolled to be between 4% and 10% and the rotation speed for formingthe infrared and ultraviolet mixed absorbing film A2 is controlledbetween 400 rpm and 650 rpm.

The infrared and ultraviolet mixed absorbing film A2 of this embodimentsatisfies the following conditions: in the infrared band, the differenceof between the wavelength with the transmittance at 80% of the infraredand ultraviolet mixed absorbing film A2 and the wavelength with thereflectivity at 80% of the first multilayer film R1 falls in the rangebetween 135 nm and 145 nm, the difference of between the wavelength withthe transmittance at 50% of the infrared and ultraviolet mixed absorbingfilm A2 and the wavelength with the reflectivity at 50% of the firstmultilayer film R1 falls in the range between 75 nm and 90 nm, and thedifference of between the wavelength with the transmittance at 20% ofthe infrared and ultraviolet mixed absorbing film A2 and the wavelengthwith the reflectivity at 20% of the first multilayer film R1 falls inthe range between 25 nm and 45 nm; in the ultraviolet band, thedifference of between the wavelength with the transmittance at 80% ofthe infrared and ultraviolet mixed absorbing film A2 and the wavelengthwith the reflectivity at 80% of the first multilayer film R1 falls inthe range between 23 nm and 40 nm, the difference between the wavelengthwith the transmittance at 50% of the infrared and ultraviolet mixedabsorbing film A2 and the wavelength with the reflectivity at 50% of thefirst multilayer film R1 ranges between 3 nm and 13 nm, and thedifference between the wavelength with the transmittance at 20% of theinfrared and ultraviolet mixed absorbing film A2 and the wavelength withthe reflectivity at 20% of the first multilayer film R1 ranges between−15 nm and 0 nm.

When the infrared and ultraviolet mixed absorbing film A2 of thisembodiment satisfies the above conditions, in the infrared band, thedifference between the incident angle 0 degrees to 30 degrees with thetransmittance at 50% of the infrared and ultraviolet mixed absorbingfilm A2 is less than 2 nm, and the difference between the incident angle0 degrees to 30 degrees with the transmittance at 20% of the infraredand ultraviolet mixed absorbing film A2 is less than 6 nm; in theultraviolet band, the difference between the incident angle 0 degrees to30 degrees with the transmittance at 50% of the infrared and ultravioletmixed absorbing film A2 ranges between −1 nm and 2 nm, and thedifference between the incident angle 0 degrees to 30 degrees with thetransmittance at 20% of the infrared and ultraviolet mixed absorbingfilm A2 is less than 9 nm. This also indicates the offset of thespectrum curves between the incident angles from 0 degrees to 30 degreesfor the infrared and ultraviolet mixed absorbing film A2 is small. Theproblems of color shift, chromatic aberration, stray light and ghostingcaused by the coating of the near-infrared filter is effectively solved.

Table 3 illustrates the difference (IR(λ_(T80%))−UV(λ_(T80%))) betweenthe wavelength with the transmittance at 80% in the infrared band andthe wavelength with the transmittance at 80% in the ultraviolet band forthe infrared and ultraviolet mixed absorbing film A2, the difference(IR(λ_(T50%))−UV(λ_(T50%))) between the wavelength with thetransmittance at 50% in the infrared band and the wavelength with thetransmittance at 50% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2, and the difference(IR(λ_(T20%))−UV(λ_(T20%))) between the wavelength with thetransmittance at 20% in the infrared band and the wavelength with thetransmittance at 20% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2.

TABLE 3 Maximum Minimum Average IR(λ_(T80%))- UV(λ_(T80%)) 161 126 140IR(λ_(T50%))- UV(λ_(T50%)) 237 196 208 IR(λ_(T20%))- UV(λ_(T20%)) 308245 261

It may be appreciated that the difference between the wavelength withthe transmittance at 80% in the infrared band and the wavelength withthe transmittance at 80% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2 ranges between 126 nm and 161 nm,the difference between the wavelength with the transmittance at 50% inthe infrared band and the wavelength with the transmittance at 50% inthe ultraviolet band for the infrared and ultraviolet mixed absorbingfilm A2 ranges between 196 nm and 237 nm, and the difference between thewavelength with the transmittance at 20% in the infrared band and thewavelength with the transmittance at 20% in the ultraviolet band for theinfrared and ultraviolet mixed absorbing film A2 ranges between 245 nmand 308 nm.

In the spectrum of the infrared and ultraviolet mixed absorbing film A2of this embodiment, the ratio of the light transmission area of thewavelength less than 450 nm to the light penetration area of thewavelength between 650 nm and 700 nm is less than 10. That is, thespectrum curves of the infrared band and the ultraviolet band of theinfrared and ultraviolet mixed layer absorption film A2 are symmetrical.This also illustrates that the spectrum curve of the infrared andultraviolet mixed layer absorption film A2 does not shift to theultraviolet band or the infrared band. Therefore, the non-visible regiondoes not interfere with the function of the CMOS sensing element,thereby reducing the occurrence of ghosting.

The above effects can also be attained by replacing the infrared andultraviolet mixed layer absorption film A2 of the present embodimentwith an infrared absorbing structure and an ultraviolet absorbingstructure separately (as shown in FIG. 4). The transparent substrate ofthe infrared ray and ultraviolet mixed absorbing film A2 of the presentembodiment may include an infrared absorbing coloring material toachieve the above effects.

Third Embodiment

In view of the structure of the absorption type near-infrared filter ofthe third embodiment, the difference between the thickness of the firstmultilayer film and the thickness of the second multilayer film is lessthan 1000 nm. The thickness of the first multilayer film and thethickness of the second multilayer film of this embodiment rangesbetween 3300 nm and 3900 nm respectively. In other words, the firstmultilayer film and the second multilayer film of the present embodimentare symmetrically coated, as shown in FIG. 2.

Table 4 provides the actual data for ten sets of absorption films. Theabsorption film of the embodiment is a single infrared absorption filmA1. The weight percentage of the infrared absorbing dye of the infraredabsorbing structure A1 of each set is different. The rotating speed forforming the infrared absorbing structure A1 between 400 rpm and 650 rpm.Refer to FIG. 7 illustrating the ninth transmittance spectrum curve 41,the tenth transmittance spectrum curve 42, the eleventh transmittancespectrum curve 43, the twelfth transmittance spectrum curve 44, and thethird reflectivity spectrum curve 45. The ninth transmittance spectrumcurve 41, the tenth transmittance spectrum curve 42, the eleventhtransmittance spectrum curve 43, and the twelfth transmittance spectrumcurve 44 respectively illustrate the transmittance spectrum curve of theinfrared absorption film A1 in the infrared band for No. 1, No. 2, No. 5and No. 10 in the following table. The third reflectivity spectrum curve45 is a reflectivity spectrum curve of the first multilayer film R1.

According to the spectrum curve of the infrared absorbing structure A1and the first multilayer film R1 (FIG. 7), in the infrared band, thedifference (A1 (λ_(T80%))−R1 (λ_(R80%))) between the wavelength(λ_(T80%)) with the transmittance at 80% of the infrared absorption filmA1 and the wavelength (λ_(R80%)) with the reflectivity at 80% of thefirst multilayer film R1, the difference (A1 (λ_(T50%))−R1 (λ_(R50%)))between the wavelength (λ_(T50%)) with the transmittance at 50% of theinfrared absorption film A1 and the wavelength (λ_(R50%)) with thereflectivity at 50% of the first multilayer film R1, the difference (A1(λ_(T20%))−R1 (λ_(R20%))) between the wavelength (λ_(T20%)) with thetransmittance at 20% of the infrared absorption film A1 and thewavelength (λ_(R20%)) with the reflectivity at 20% of the firstmultilayer film R1, the difference (Δλ_((0°−30°)T50%)) between theincident angle 0 degrees to 30 degrees with the transmittance at 50% ofthe infrared absorption film A1, and the difference (Δλ_((0°−30°)T20%))between the incident angle 0 degrees to 30 degrees with thetransmittance at 20% of the infrared absorption film A1 are calculated.

TABLE 4 No. 1 2 3 4 5 Infrared absorbing dye 0.68 0.94 1.24 1.47 1.53(%) Transparent resin (%) 100 100 100 100 100 A1 (λ_(T80%))-R1(λ_(R80%))122.7 126.9 129.7 130.6 131.3 (nm) A1 (λ_(T50%))-R1(λ_(R50%)) 59.4 69.075.1 77.0 77.8 (nm) A1 (λ_(T20%))-R1(λ_(R20%)) 5.8 21.3 28.3 30.8 32.2nm) Δλ_((0°-30°)T50%) 3.8 3.2 1.8 1.7 1.6 Δλ_((0°-30°)T20%) 20.4 10.56.3 5.4 4.6 No. 6 7 8 9 10 Infrared absorbing dye 1.58 1.75 1.83 2.022.73 (%) Transparent resin (%) 100 100 100 100 100 A1(λ_(T80%))-R1(λ_(R80%)) 132.4 133.1 134.1 135.3 136.2 (nm) A1(λ_(T50%))-R1(λ_(R50%)) 80.0 80.9 81.5 84.2 84.6 (nm) A1(λ_(T20%))-R1(λ_(R20%)) 34.3 35.6 37.6 39.5 41.9 nm) Δλ_((0°-30°)T50%)1.5 1.5 1.5 1.6 1.7 Δλ_((0°-30°)T20%) 4.3 3.6 3.2 3.1 2.8

It may be summarized from No. 4 to No. 10 in the above Table 4. Theweight percentage of the infrared absorbing dye contained in theinfrared absorbing structure A1 is controlled to be between 1% and 3%,and the rotation speed for forming the infrared absorbing structure A1is controlled between 400 rpm and 650 rpm. The spectrum of each of theinfrared absorbing structure A1 satisfies the following conditions: thedifference of between the wavelength with the transmittance at 80% ofthe infrared absorption film A1 and the wavelength with the reflectivityat 80% of the first multilayer film R1 falls in the range between 130 nmand 137 nm, the difference of between the wavelength with thetransmittance at 50% of the infrared absorption film A1 and thewavelength with the reflectivity at 50% of the first multilayer film R1falls in the range between 77 nm and 85 nm, and the difference ofbetween the wavelength with the transmittance at 20% of the infraredabsorption film A1 and the wavelength with the reflectivity at 20% ofthe first multilayer film R1 falls in the range between 30 nm and 42 nm.

When the spectrum of the infrared absorbing structure A1 satisfies theabove conditions, the difference between the incident angle 0 degrees to30 degrees with the transmittance at 50% of the infrared absorption filmA1 is less than 2 nm, and the difference between the incident angle 0degrees to 30 degrees with the transmittance at 20% of the infraredabsorption film A1 is less than 6 nm. This indicates the offset of thespectrum curves between the incident angles from 0 degrees to 30 degreesfor the infrared absorption film A1 is small. The problems of colorshift, chromatic aberration, stray light and ghosting caused by thecoating of the near-infrared filter is effectively solved. Thetransparent substrate of the infrared absorbing structure A1 of thepresent embodiment may also contain an infrared absorbing coloringmaterial to achieve the above effects.

Fourth Embodiment

Different from the absorption type near-infrared filter in the thirdembodiment, the absorption type near-infrared filter of the presentembodiment adopts an infrared and ultraviolet mixed absorbing film A2,as shown in FIG. 3.

Table 2 below provides actual data for ten sets of absorption films. Theabsorption film is an infrared and ultraviolet mixed layer absorptionfilm A2. The weight percentage of the infrared absorbing dye and theultraviolet absorbing dye of each infrared and ultraviolet mixed layerabsorption film A2 is different. The rotating speed for coating formingthe infrared absorbing structure A2 between 400 rpm and 650 rpm. Referto FIG. 7 and FIG. 8, the spectrum curves in the infrared band of theinfrared and ultraviolet mixed layer absorption film A2 and the firstmultilayer film R1 of this embodiment are similar to the infraredabsorption film A1 and the first multilayer film R1 of the secondembodiment. Therefore, the spectrum curve of the infrared andultraviolet mixed layer absorption film A2 in the infrared band of thisembodiment may refer to FIG. 7. FIG. 8 includes the thirteenthtransmittance spectrum curve 51, the fourteenth transmittance spectrumcurve 52, the fifteenth transmittance spectrum curve 53, the sixteenthtransmittance spectrum curve 54 and the fourth reflectivity spectrumcurve 55. The thirteenth transmittance spectrum curve 51, the fourteenthtransmittance spectrum curve 52, the fifteen transmittance spectrumcurve 53, and the sixteenth transmittance spectrum curve 54 respectivelyillustrate the transmittance spectrum curve of the infrared andultraviolet mixed layer absorption film A2 in the ultraviolet band forNo. 1, No. 2, No. 5 and No. 10 in the following table. The fourthreflectivity spectrum curve 55 is a reflectivity spectrum curve of thesecond multilayer film R2 in the ultraviolet band.

According to the spectrum curve of the infrared and ultraviolet mixedlayer absorption film A2, the first multilayer film R1 and the secondmultilayer film R₂ (as shown in FIG. 7 and FIG. 8), in the infraredband, the difference (A2(λ_(T80%))−R1(λ_(R80%))) between the wavelengthwith the transmittance at 80% of the infrared and ultraviolet mixedlayer absorption film A2 and the wavelength with the reflectivity at 80%of the first multilayer film R1, the difference(A2(λ_(T50%))−R1(λ_(R50%))) between the wavelength with thetransmittance at 50% of the infrared and ultraviolet mixed layerabsorption film A2 and the wavelength with the reflectivity at 50% ofthe first multilayer film R1, the difference (A2 (λ_(T20%))−R1(λ_(R20%))) between the wavelength with the transmittance at 20% of theinfrared and ultraviolet mixed layer absorption film A2 and thewavelength with the reflectivity at 20% of the first multilayer film R1,the difference (Δλ_((0°−30°)T50%)) between the incident angle 0 degreesto 30 degrees with the transmittance at 50% of the infrared andultraviolet mixed layer absorption film A2, and the difference(Δλ_((0°−30°)T20%)) between the incident angle 0 degrees to 30 degreeswith the transmittance at 20% of the infrared and ultraviolet mixedlayer absorption film A2 are calculated.

In the ultraviolet band, the difference (A2(λ_(T80%))−R₂(λ_(R80%)))between the wavelength with the transmittance at 80% of the infrared andultraviolet mixed layer absorption film A2 and the wavelength with thereflectivity at 80% of the second multilayer film R₂, the difference(A2(λ_(T50%))−R₂(λ_(R50%))) between the wavelength with thetransmittance at 50% of the infrared and ultraviolet mixed layerabsorption film A2 and the wavelength (λ_(R50%)) with the reflectivityat 50% of the second multilayer film R₂, the difference(A2(λ_(T20%))−R₂(λ_(R20%))) between the wavelength with thetransmittance at 20% of the infrared and ultraviolet mixed layerabsorption film A2 and the wavelength (λ_(R20%)) with the reflectivityat 20% of the second multilayer film R₂, the difference(Δλ_((0°−30°)T50%)) between the incident angle 0 degrees to 30 degreeswith the transmittance at 50% of the infrared and ultraviolet mixedlayer absorption film A2, and the difference (Δλ_((0°−30°)T20%)) betweenthe incident angle 0 degrees to 30 degrees with the transmittance at 20%of the infrared and ultraviolet mixed layer absorption film A2 arecalculated.

TABLE 5 No. 1 2 3 4 5 Infrared absorbing dye 0.68 0.94 1.24 1.47 1.53(%) Ultraviolet absorbing dye 2.7 3.5 4.2 5.28 7.68 (%) Transparentresin (%) 100 100 100 100 100 No. 6 7 8 9 10 Infrared absorbing dye 1.581.75 1.83 2.02 2.73 (%) Ultraviolet absorbing dye 7.94 8.58 8.94 9.239.54 (%) Transparent resin (%) 100 100 100 100 100 IN THE INFRARED BANDNo. 1 2 3 4 5 A2(λ_(T80%))-R1 (λ_(R80%)) (nm) 122.7 126.9 129.7 130.6131.3 A2(λ_(T50%))-R1(λ_(R50%)) (nm) 59.4 69.0 75.1 77.0 77.8A2(λ_(T20%))-R1(λ_(R20%)) (nm) 5.8 21.3 28.3 30.8 32.2 Δλ_((0°-30°)T50%)3.8 3.2 1.8 1.7 1.6 Δλ_((0°-30°)T20%) 20.4 10.5 6.3 5.4 4.6 No. 6 7 8 910 A2(λ_(T80%))-R1 (λ_(R80%)) (nm) 132.4 133.1 134.1 135.3 136.2A2(λ_(T50%))-R1(λ_(R50%)) (nm) 80.0 80.9 81.5 84.2 84.6A2(λ_(T20%))-R1(λ_(R20%)) (nm) 34.3 35.6 37.6 39.5 41.9Δλ_((0°-30°)T50%) 1.5 1.5 1.5 1.6 1.7 Δλ_((0°-30°)T20%) 4.3 3.6 3.2 3.12.8 IN THE ULTRAVOILET BAND No. 1 2 3 4 5 A2(λ_(T80%))-R₂(λ_(R80%)) (nm)15.8 19.5 23.56 25.4 27.1 A2(λ_(T50%))-R₂(λ_(R50%)) (nm) −2.4 0.5 4.686.7 8.3 A2(λ_(T20%))-R₂(λ_(R20%)) (nm) −25.1 −17.7 −9.8 −6.7 −4.4Δλ_((0°-30°)T50%) 7.8 5.3 1.9 0.6 −0.8 Δλ_((0°-30°)T20%) 10.6 10.4 8.97.5 6.0 No. No. 6 7 8 9 10 A2(λ_(T80%))-R₂(λ_(R80%)) (nm) 29.0 30.3 32.033.8 36.1 A2(λ_(T50%))-R₂(λ_(R50%)) (nm) 9.6 10.7 11.7 12.6 13.5A2(λ_(T20%))-R₂(λ_(R20%)) (nm) −2.5 −0.9 0.3 1.5 2.5 Δλ_((0°-30°)T50%)−0.9 −1.1 −1 −1 −1 Δλ_((0°-30°)T20%) 4.8 3.4 2.6 1.8 1.2

It may be summarized from No. 4 to No. 10 in the above Table 5. Theweight percentage of the infrared absorbing dye contained in theinfrared and ultraviolet mixed absorbing film A2 is controlled to bebetween 1% and 3%, the weight percentage of the ultraviolet absorbingdye contained in the infrared and ultraviolet mixed absorbing film A2 iscontrolled to be between 4% and 10% and the rotation speed for formingthe infrared and ultraviolet mixed absorbing film A2 is controlledbetween 400 rpm and 650 rpm. The infrared and ultraviolet mixedabsorbing film A2 of this embodiment satisfies the following conditions:in the infrared band, the difference of between the wavelength with thetransmittance at 80% of the infrared and ultraviolet mixed absorbingfilm A2 and the wavelength with the reflectivity at 80% of the firstmultilayer film R1 falls in the range between 130 nm and 137 nm, thedifference of between the wavelength with the transmittance at 50% ofthe infrared and ultraviolet mixed absorbing film A2 and the wavelengthwith the reflectivity at 50% of the first multilayer film R1 falls inthe range between 77 nm and 85 nm, and the difference of between thewavelength with the transmittance at 20% of the infrared and ultravioletmixed absorbing film A2 and the wavelength with the reflectivity at 20%of the first multilayer film R1 falls in the range between 30 nm and 42nm.

In the ultraviolet band, the difference of between the wavelength withthe transmittance at 80% of the infrared and ultraviolet mixed absorbingfilm A2 and the wavelength with the reflectivity at 80% of the secondmultilayer film R₂ falls in the range between 25 nm and 37 nm, thedifference of between the wavelength with the transmittance at 50% ofthe infrared and ultraviolet mixed absorbing film A2 and the wavelengthwith the reflectivity at 50% of the second multilayer film R₂ falls inthe range between 6 nm and 14 nm, and the difference of between thewavelength with the transmittance at 20% of the infrared and ultravioletmixed absorbing film A2 and the wavelength with the reflectivity at 20%of the second multilayer film R₂ falls in the range between −6 nm and2.5 nm.

When the infrared and ultraviolet mixed absorbing film A2 of thisembodiment satisfies the above conditions, in the infrared band, thedifference between the incident angle 0 degrees to 30 degrees with thetransmittance at 50% of the infrared and ultraviolet mixed absorbingfilm A2 is less than 2 nm, and the difference between the incident angle0 degrees to 30 degrees with the transmittance at 20% of the infraredand ultraviolet mixed absorbing film A2 is less than 6 nm; in theultraviolet band, the difference between the incident angle 0 degrees to30 degrees with the transmittance at 50% of the infrared and ultravioletmixed absorbing film A2 ranges between −1 nm and 2 nm, and thedifference between the incident angle 0 degrees to 30 degrees with thetransmittance at 20% of the infrared and ultraviolet mixed absorbingfilm A2 is less than 8 nm. This also indicates the offset of thespectrum curves between the incident angles from 0 degrees to 30 degreesfor the infrared and ultraviolet mixed absorbing film A2 is small. Theproblems of color shift, chromatic aberration, stray light and ghostingcaused by the coating of the near-infrared filter is effectively solved.

Table 6 illustrates the difference (IR(λ_(T80%))−UV(λ_(T80%))) betweenthe wavelength with the transmittance at 80% in the infrared band andthe wavelength with the transmittance at 80% in the ultraviolet band forthe infrared and ultraviolet mixed absorbing film A2, the difference(IR(λ_(T50%))−UV(λ_(T50%))) between the wavelength with thetransmittance at 50% in the infrared band and the wavelength with thetransmittance at 50% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2, and the difference(IR(λ_(T20%))−UV(λ_(T20%))) between the wavelength with thetransmittance at 20% in the infrared band and the wavelength with thetransmittance at 20% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2.

TABLE 6 Maximum Minimum Average IR(λ_(T80%))- UV(λ_(T80%)) 164 130 144IR(λ_(T50%))- UV(λ_(T50%)) 239 197 212 IR(λ_(T20%))- UV(λ_(T20%)) 309245 262

It may be appreciated that the difference between the wavelength withthe transmittance at 80% in the infrared band and the wavelength withthe transmittance at 80% in the ultraviolet band for the infrared andultraviolet mixed absorbing film A2 ranges between 130 nm and 164 nm,the difference between the wavelength with the transmittance at 50% inthe infrared band and the wavelength with the transmittance at 50% inthe ultraviolet band for the infrared and ultraviolet mixed absorbingfilm A2 ranges between 197 nm and 239 nm, and the difference between thewavelength with the transmittance at 20% in the infrared band and thewavelength with the transmittance at 20% in the ultraviolet band for theinfrared and ultraviolet mixed absorbing film A2 ranges between 245 nmand 309 nm.

In the spectrum of the infrared and ultraviolet mixed absorbing film A2of this embodiment, the ratio of the light transmission area of thewavelength less than 450 nm to the light penetration area of thewavelength between 650 nm and 700 nm is less than 10. That is, thespectrum curves of the infrared band and the ultraviolet band of theinfrared and ultraviolet mixed layer absorption film A2 are symmetrical.This also illustrates that the spectrum curve of the infrared andultraviolet mixed layer absorption film A2 does not shift to theultraviolet band or the infrared band. Therefore, the non-visible regiondoes not interfere with the function of the CMOS sensing element,thereby reducing the occurrence of ghosting.

The above effects can also be attained by replacing the infrared andultraviolet mixed layer absorption film A2 of the present embodimentwith an infrared absorbing structure and an ultraviolet absorbingstructure separately. The transparent substrate of the infrared ray andultraviolet mixed absorbing film A2 of the present embodiment mayinclude an infrared absorbing coloring material to achieve the aboveeffects.

In summary, the present disclosure discloses an absorption typenear-infrared filter. The content of the infrared absorbing dye or/andthe ultraviolet absorbing dye in the absorption film of the absorptiontype near-infrared filter of the present disclosure is adjusted suchthat the absorption film may at least satisfy the conditions: in theinfrared band, the difference between the wavelength with thetransmittance at 80% of the absorption film and the wavelength with thereflectivity at 80% of the first multilayer film ranges between 130 nmand 145 nm; the difference between the wavelength with the transmittanceat 50% of the absorption film and the wavelength with the reflectivityat 50% of the first multilayer film ranges between 75 nm and 90 nm; thedifference between the wavelength with the transmittance at 20% of theabsorption film and the wavelength with the reflectivity at 20% of thefirst multilayer film ranges between 25 nm and 45 nm; the absolutedifference between the wavelength with the transmittance at 80% of theabsorption film and the wavelength with the reflectivity at 50% of theabsorption film is lower than 50 nm; and the absolute difference betweenthe wavelength with the transmittance at 50% of the absorption film andthe wavelength with the transmittance at 20% of the absorption film islower than 42 nm. The above various embodiments show that the absorptiontype near-infrared filter of the present disclosure can avoid theproblems such as color shift, chromatic aberration, stray light andghosting, thereby improving the quality of the picture.

It is to be understood that the term “comprises”, “comprising”, or anyother variants thereof, is intended to encompass a non-exclusiveinclusion, such that a process, method, article, or device of a seriesof elements not only includes those elements but also includes otherelements that are not explicitly listed, or elements that are inherentto such a process, method, article, or device. An element defined by thephrase “comprising a . . . ” does not exclude the presence of the sameelement in the process, method, article, or device that comprises theelement.

Although the present disclosure has been explained in relation to itspreferred embodiment, it does not intend to limit the presentdisclosure. It will be apparent to those skilled in the art havingregard to this present disclosure that other modifications of theexemplary embodiments beyond those embodiments specifically describedhere may be made without departing from the spirit of the disclosure.Accordingly, such modifications are considered within the scope of thedisclosure as limited solely by the appended claims.

What is claimed is:
 1. An absorption type near-infrared filter, comprising: a first multilayer film; a second multilayer film; and an absorption film between the first multilayer film and the second multilayer film, the absorption film comprising an infrared absorbing dye with a weight percentage between 1% and 3%; wherein in the infrared band, the difference between the wavelength with the transmittance at 80% of the absorption film and the wavelength with the reflectivity at 80% of the first multilayer film ranges between 130 nm and 145 nm; the difference between the wavelength with the transmittance at 50% of the absorption film and the wavelength with the reflectivity at 50% of the first multilayer film ranges between 75 nm and 90 nm; the difference between the wavelength with the transmittance at 20% of the absorption film and the wavelength with the reflectivity at 20% of the first multilayer film ranges between 25 nm and 45 nm.
 2. The absorption type near-infrared filter according to claim 1, wherein the absolute difference between the wavelength with the transmittance at 80% of the absorption film and the wavelength with the transmittance at 50% of the absorption film is lower than 50 nm; and the absolute difference between the wavelength with the transmittance at 50% of the absorption film and the wavelength with the transmittance at 20% of the absorption film is lower than 42 nm.
 3. The absorption type near-infrared filter according to claim 1, wherein the absorption film comprises a transparent substrate and an infrared absorbing structure formed on the transparent substrate, and the infrared absorbing dye is distributed in the infrared absorbing structure.
 4. The absorption type near-infrared filter according to claim 3, wherein the transparent substrate further comprises an infrared absorption pigment.
 5. The absorption type near-infrared filter according to claim 1, wherein the absorption film further comprises an ultraviolet absorbing dye in a weight percentage between 4% and 10%.
 6. The absorption type near-infrared filter according to claim 5, wherein in the ultraviolet band, the difference between the wavelength with the transmittance at of the absorption film and the wavelength with the reflectivity at 80% of the first multilayer film ranges between 23 nm and 40 nm; the difference between the wavelength with the transmittance at 50 % of the absorption film 11 and the wavelength with the reflectivity at 50% of the first multilayer film 10 ranges between 3 nm and 14 nm; the difference between the wavelength with the transmittance at 20% of the absorption film 11 and the wavelength with the reflectivity at 20% of the first multilayer film 10 ranges between −15 nm and 2.5 nm.
 7. The absorption type near-infrared filter according to claim 6, wherein in the ultraviolet band, the absolute difference between the wavelength with the transmittance at 80% of the absorption film and the wavelength with the transmittance at 50% of the absorption film is lower than 23 nm; the absolute difference between the wavelength with the transmittance at 50 % of the absorption film and the wavelength with the transmittance at 20% of the absorption film is lower than 16 nm.
 8. The absorption type near-infrared filter according to claim 6, wherein in the ultraviolet band, the difference between the wavelength with the transmittance at 80% of the absorption film in the infrared band and the wavelength with the transmittance at 80% of the absorption film in the ultraviolet band ranges between 126 nm and 164 nm; the difference between the wavelength with the transmittance at 50% of the absorption film in the infrared band and the wavelength with the transmittance at 50% of the absorption film in the ultraviolet band ranges between 195 nm and 239 nm; the difference between the wavelength with the transmittance at 20% of the absorption film in the infrared band and the wavelength with the transmittance at 20% of the absorption film in the ultraviolet band ranges between 244 nm and 309 nm.
 9. The absorption type near-infrared filter according to claim 5, wherein the absorption film comprises a transparent substrate and an infrared and ultraviolet mixed layer formed on the transparent substrate, and the infrared absorbing dye and the ultraviolet absorbing dye are distributed in the infrared absorbing structure.
 10. The absorption type near-infrared filter according to claim 9, wherein the transparent substrate further comprises an infrared absorption pigment.
 11. The absorption type near-infrared filter according to claim 5, wherein the absorption film comprises a transparent substrate and an infrared and ultraviolet layered absorbing film formed on the transparent substrate; the infrared and ultraviolet layered absorbing film comprises an infrared absorption layer and an ultraviolet absorption layer; the infrared absorption layer is formed on the transparent substrate, the ultraviolet absorption layer is formed on the infrared absorption layer, the infrared absorbing dye is distributed in the infrared absorbing structure, and the ultraviolet absorbing dye is distributed in the ultraviolet absorbing structure.
 12. The absorption type near-infrared filter according to claim 11, wherein the transparent substrate further comprises an infrared absorption pigment.
 13. The absorption type near-infrared filter according to claim 5, wherein the absorption film comprises a transparent substrate and an infrared and ultraviolet layered absorbing film formed on the transparent substrate; the infrared and ultraviolet layered absorbing film comprises an infrared absorption layer and an ultraviolet absorption layer; the ultraviolet absorption layer is formed on the transparent substrate, the infrared absorption layer is formed on the ultraviolet absorption layer, the infrared absorbing dye is distributed in the infrared absorbing structure, and the ultraviolet absorbing dye is distributed in the ultraviolet absorbing structure.
 14. The absorption type near-infrared filter according to claim 12, wherein the transparent substrate further comprises an infrared absorption pigment.
 15. The absorption type near-infrared filter according to claim 1, wherein the difference between the thickness of the first multilayer film and the thickness of the second multilayer film is greater than 3000 nm, and in the infrared band, the difference of between the wavelength with the transmittance at 80% of the absorption film and the wavelength with the reflectivity at 80% of the first multilayer film falls in the range between 135 nm and 145 nm.
 16. The absorption type near-infrared filter according to claim 1, wherein the difference between the thickness of the first multilayer film and the thickness of the second multilayer film is less than 1000 nm, in the infrared band, the difference of between the wavelength with the transmittance at 80% of the infrared absorption film and the wavelength with the reflectivity at 80% of the first multilayer film falls in the range between 130 nm and 137 nm, the difference of between the wavelength with the transmittance at 50% of the infrared absorption film and the wavelength with the reflectivity at 50% of the first multilayer film falls in the range between 77 nm and 85 nm, and the difference of between the wavelength with the transmittance at 20% of the infrared absorption film and the wavelength with the reflectivity at 20% of the first multilayer film falls in the range between 30 nm and 42 nm.
 17. The absorption type near-infrared filter according to claim 8, wherein the difference between the thickness of the first multilayer film and the thickness of the second multilayer film is greater than 3800 nm, and in the ultraviolet band, the difference of between the wavelength with the transmittance at 50% of the absorption film and the wavelength with the reflectivity at 50% of the first multilayer film falls in the range between 3 nm and 13 nm, and the difference of between the wavelength with the transmittance at 20% of the absorption film and the wavelength with the reflectivity at 20% of the first multilayer film falls in the range between −15 nm and 0 nm.
 18. The absorption type near-infrared filter according to claim 17, wherein the difference between the wavelength with the transmittance at of the absorption film in the infrared band and the wavelength with the reflectivity at 80% of the absorption film in the ultraviolet band ranges between 126 nm and 161 nm.
 19. The absorption type near-infrared filter according to claim 8, wherein the difference between the thickness of the first multilayer film and the thickness of the second multilayer film is less than 1000 nm; in the ultraviolet band, the difference of between the wavelength with the transmittance at 80% of the absorbing structure and the wavelength with the reflectivity at 80% of the first multilayer film falls in the range between 25 nm and 37 nm, the difference of between the wavelength with the transmittance at 50% of the absorbing structure and the wavelength with the reflectivity at 50% of the first multilayer film falls in the range between 6 nm and 14 nm, and the difference of between the wavelength with the transmittance at 20% of the absorbing structure and the wavelength with the reflectivity at 20% of the first multilayer film falls in the range between −6 nm and 2.5 nm.
 20. The absorption type near-infrared filter according to claim 19, wherein the difference between the wavelength with the transmittance at 80% in the infrared band and the wavelength with the transmittance at 80% in the ultraviolet band for the absorbing structure ranges between 130 nm and 164 nm. 